The present invention relates to multifunctional hybrid materials and a method for making the materials, which enhance the survivability in an aggressive environment such as low-earth orbit and have low coefficients of thermal expansion and low density.
The development of the new multifunctional materials for the aerospace application is an urgent demand. There are several important requirements for the materials for the aerospace application. The first issue is the rapid change of temperature in aerospace environment. The mismatch of the coefficients of thermal expansion between the polymer (typically 40-60 ppm/K) and carbon fiber (˜0 ppm/K) in the traditional composite can be the reason for the fracture and degradation of the composite materials. In addition, the mismatch of the coefficients of thermal expansion between the titanium (˜10 ppm/K) and polymer adhesive is also significant, so it is important to reduce the coefficient of thermal expansion of the polymer. Here the reduction of the coefficient of thermal expansion was achieved by the introduction of the negative-CTE filler such as Zirconium Tungstate (ZrW2O8). ZrW2O8 is a ceramic with a p.p.m.K−1) over a very wide temperature range (from 0.3° K to 1050° K), and the isotropic negative CTE.
The second very important issue for the materials out in space application is the weight of the materials. The low density of the material is critical. The introduction of the microballoon into the system will significantly reduce the density of the polymer and reduce the coefficient of thermal expansion simultaneously. The third important issue is that the polymers will easily erode in an aerospace environment such as low earth orbit, where atomic oxygen flux is very high. The introduction of the silicate nanolayers significantly improves the survivability of the materials in an aerospace environment. The improved survivability of the materials after the incorporation of the silicate nanolayers is due to the formation ceramic-like inorganic layers, which can prevent further erosion of the polymeric materials.
Polymer membrane mirrors offer the greatest potential for large aperture extremely lightweight mirror systems. For example, they could be deployable, thus decreasing payload size. They would be able to be made very large (10 s of meters in diameter) but still be extremely low mass. Simultaneously, they are accompanied by many polymer related disadvantages (low environmental stability and large CTE). The system in this invention can also be used in the fabrication of lightweight mirror assemblages since this system is a light-weight structural substrate made from syntactic foams and has a lower out gassing rate in space environments, CTE tailorability, and density reduction.
The objective of this invention is to provide a new hybrid material, which can have low density, low coefficients of thermal expansion and very high survivability in space.
Other objectives and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description or may be learned by the practice of the invention. The objects and advantages of the invention may be realized by means of the combinations particularly described in the appended claims.